Gentlemen, you have probably been asked this question plenty of time.But I have been knife making for about a year now and I want to try something a little different. I have a majestic two burner knife making forge and I'm running a 100lbs propane bottle at 12psi. I cannot reach forge welding temperature (yellow or white heat). Even when I am starting with a piece of steal 3/8 or a 1/4 inch thick I still cannot get it any hotter than bright orange. If anyone has any advice or suggestions please fire away.
Add a blower or put some compressed air into the gas stream and you should reach 2200 deg f at about 8 psi of propane.I use a needle valve and air regulator and put a small amount of air into the gas stream. If you have a big dragons breath on the outside of the forge you are burning gas out of the forge.If you suck the flame way inside the forge you are adding to much air and cooling off the steel. You want just a small amount of orange flame at the door of the forge for maximum temperature. This is real easy so see if you have a pyrometer and can measure the temp unfortunately they don't last very long at this temp and especially with borax. Mine is a N type pyrometer and I coat the probe with Vesuvius Super 3000 refractory,and it has been working for a couple of years.
IF YOU CAN GET A BLOWER FROM THOSE NEW HIGH EFFICIENCY WATER HEATER THEY WORK WELL do YOU HAVE AN AIR COMPRESSOR ? TAKE AND PUT A VALVE ON THE END OF THE HOSE WITH A PIECE OF COPPER TUBING AND STICK IT IN THE END OF BURNER ADJUST THE AIR FLOW UNTIL IT WORKS FOR YOU.
run a line down the bore of the tube that the propane is flowing into the burner. I assume you have a burner of some sort in this forge????? you have to have a regulator on the air line or as the air pressure goes up and down the flow with also change